Devices of the kind to which the present invention refers are disclosed for example in U.S. Pat. Nos. 5,685,722 and 5,600,730.
U.S. Pat. No. 5,685,722 is directed to goggles incorporating an electronic timer and display for displaying the times of a swimmer with a display accessible to a swimmer connected to the goggles. An accelerometer is used to determine a swimmer's movements with an electronic circuit for processing the information from the accelerometer to determine a swimmer's movements and time between movements.
U.S. Pat. No. 5,600,730 is directed to a swimming training device that may be part of an overall training system. The device is deployable releasably in a swimming cap and can receive electromagnetic wave signals. The device can then convert the signals into electrical charges which are then translated into audible sound. The system includes the cap with the receiving device and a transmitting source. The transmitting source allows the broadcasting of verbal instructions, as well as music and timing signals.